A hormone naturally released during sex, childbirth and breastfeeding could provide a new treatment for anorexia, according to research.

Oxytocin - dubbed the "love hormone" or the "cuddle chemical" - has been shown to alter anorexics' tendencies to fixate on images of high calorie foods and larger body shapes, one study has shown. A further piece of research has found that the hormone changed anorexic patients' responses to images of angry and disgusted faces.

Research published in the journal Psychoneuroendocrinology revealed that anorexics who were shown images of food and fat body parts reduced their focus on images of food and fat body parts after being given oxytocin using a nasal spray.

The same 31 participants in a study published in the journal PLOS ONE testing their reactions to facial expressions such as anger, disgust and happiness, were shown to be less likely to focus on "disgust" faces. They were also less likely to avoid looking at angry faces.

Prof Youl-Ri Kim, from Inje University in Seoul, South Korea and lead author on both studies, says: "Our research shows that oxytocin reduces patients' unconscious tendencies to focus on food, body shape, and negative emotions such as disgust.

"There is currently a lack of effective pharmacological treatments for anorexia. Our research adds important evidence to the increasing literature on oxytocin treatments for mental illnesses, and hints at the advent of a novel, ground-breaking treatment option for patients with anorexia."

Professor Janet Treasure, of King's College London Institute of Psychiatry and senior author for both studies said: "Patients with anorexia have a range of social difficulties which often start in their early teenage years, before the onset of the illness.

"These social problems, which can result in isolation, may be important in understanding both the onset and maintenance of anorexia. By using oxytocin as a potential treatment for anorexia, we are focusing on some of these underlying problems we see in patients."

She added: "This is early stage research with a small number of participants, but it's hugely exciting to see the potential this treatment could have.

"We need much larger trials, on more diverse populations, before we can start to make a difference to how patients are treated."

Anorexia is one of the leading causes of mental-health related deaths both through physical complications and suicide. Patients often have distorted images of themselves, believing that they are fat when they are not.

As well as problems with food, eating and body shape, patients with anorexia often have social difficulties including anxiety and hypersensitivity to negative emotions.